Negating all T's earned from blogs, donations, designs etc... there are three apparent paths to Color Level Black.
Fast Track to Black: It is possible, though extremely unlikely, to be able to obtain color level black with only 26 games (3 castings and 23 rookies).
Economy: Though you could technically get all the karma you need to obtain playing castings with no loss of Ts... The best economy route to Black would be to play only castings and Survivor because in Survivor you only have to pay once and if your skills at microgames are good enough (atleast better than half the other people) you should be able to merge again and again.
Something in the middle: Most people play a mix of all the games which is fun but not necessarily fast or economical.
Negating all T's earned from blogs, donations, designs etc... there are three apparent paths to Color Level Black.